A method for preparing a recyclable composite antibacterial agent for water treatment

Abstract

The application discloses a preparation method of a recyclable composite antibacterial agent for water treatment and belongs to the technical field of antibacterial material preparation. The method adopts a chemical activation method, a hydrothermal method and impregnation to prepare an AC-NiO / Fe composite antibacterial agent. The application reduces a band gap by adding Fe, improves magnetic separation performance and improves antibacterial activity. The AC-NiO / Fe composite antibacterial material can not only effectively inhibit the growth of microorganisms in water, but also can adsorb organic dyes in water and can be recycled through magnetic separation.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a recyclable composite antibacterial agent for water treatment and belongs to the technical field of antibacterial material preparation. BACKGROUND

[0002] Water resource pollution seriously threatens the ecological environment and human health, and pathogenic microorganisms and toxic pollutants are the two most threatening pollutants to human health in wastewater, the microbial pollutants can directly cause many water-borne diseases such as dysentery and typhoid fever, in addition, the toxic pollutants (for example, organic dyes) in water usually have complex aromatic functional groups and may cause mutations or teratogenesis in the biological accumulation process, therefore, it is necessary to obtain a multifunctional adsorption antibacterial agent which can simultaneously and efficiently remove pathogenic bacteria and various micro-pollutants such as organic dyes in polluted water.

[0003] For many years, traditional disinfection technologies including chlorides, ozone and ultraviolet irradiation have been widely used in water purification, however, these methods are faced with the problem of high energy consumption, and harmful by-products may be formed in the use process, which may produce genetic toxicity, cytotoxicity or carcinogenicity. Therefore, an environmentally friendly, by-product-free and economically efficient disinfection technology is imperative for water treatment, and the elimination of pathogenic microorganisms and the removal of dyes usually require multi-step treatment, long duration and high operating cost, therefore, it is necessary to develop an integrated antibacterial agent which can simultaneously eliminate bacteria and remove dyes in water, in addition, the antibacterial agent is usually directly added to water for water treatment, and therefore, chemical residues may be introduced to cause secondary pollution to the ecological environment.

[0004] So far, the research aiming at simultaneously removing dyes and killing pathogens in wastewater is still limited, and most of the currently reported materials have poor adsorption capacity and sterilization efficiency, which may limit their performance in practical application, therefore, it is necessary to develop an effective, economical and environmentally friendly adsorbent to simultaneously inactivate pathogenic bacteria and remove dyes in polluted water, and the adsorbent can also be separated and recycled, so as to achieve the purposes of saving resources and protecting the environment. SUMMARY

[0005] The application aims to prepare a recyclable antibacterial agent, and the specific preparation steps are as follows:

[0006] (1) Australian nut shells are used as raw materials, and activated carbon is prepared by a chemical activation method with phosphoric acid as an activator.

[0007] (2) NiCl2.6H2O and FeCl3.6H2O are mixed and dissolved, and the pH is adjusted.

[0008] (3) The mixed solution obtained in step (2) is transferred to a polytetrafluoroethylene-lined stainless steel autoclave for hydrothermal reaction, and the obtained precipitate is filtered, washed, and dried overnight.

[0009] (4) The dried precipitate in step (3) is calcined in a muffle furnace to obtain a NiO / Fe composite material.

[0010] (5) The NiO / Fe composite material obtained in step (4) is dissolved, and the activated carbon obtained in step (1) is added to obtain an AC-NiO / Fe composite antibacterial agent by stirring and impregnation.

[0011] Preferably, the molar concentration ratio of NiCl2·6H2O and FeCl3·6H2O in step (2) is 1:2.

[0012] Preferably, the pH in step (2) is adjusted to 11 using 1 mol / L NaOH.

[0013] Preferably, the hydrothermal reaction condition in step (3) is heating at 150℃ for 2h, the washing condition is alternating washing with distilled water and ethanol for three times, and the drying temperature is 110℃.

[0014] Preferably, the calcination condition in step (4) is calcination at 300℃ for 4h.

[0015] Preferably, the concentration of the NiO / Fe composite material in the NiO / Fe solution in step (5) is 0.025g / mL, and the mass ratio of activated carbon to NiO / Fe composite material is 0.025g / mL.

[0016] Preferably, the impregnation stirring time in step (5) is 24h, and the stirring speed is 200r / min.

[0017] The preparation method of activated carbon in the present application is a conventional chemical activation method, which is a preparation method known to those skilled in the art.

[0018] Advantages of the present application

[0019] (1) NiO can reduce the band gap by being combined with Fe, enhance light absorption and electron-hole separation, and improve antibacterial activity. After introducing Fe, the magnetic property is obviously enhanced.

[0020] (2) When the AC-NiO / Fe composite antibacterial agent is applied to actual water treatment, it can be found that the antibacterial agent has good inhibitory effect on the growth and reproduction of pathogenic microorganisms in water.

[0021] (3) The AC-NiO / Fe composite antibacterial agent exhibits good adsorption and degradation performance for dyes such as malachite green and methylene blue in water.

[0022] (4) The AC-NiO / Fe composite antibacterial agent can be recycled by magnetic separation after use, avoiding secondary pollution caused by the use of chemical materials, reducing the cost of actual application of the material, and providing important research value for preparing multifunctional antibacterial agents for water treatment. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 SEM and EDS images of the AC-NiO / Fe composite antibacterial agent prepared in Example 1.

[0024] Figure 2 XPS spectrum of the AC-NiO / Fe composite antibacterial agent prepared in Example 1, wherein figure (a) is the XPS full spectrum; figure (b) is Ni 2p; figure (c) is Fe 2p; figure (d) is O 1s.

[0025] Figure 3 EPR spectrum of the AC-NiO antibacterial agent and the AC-NiO / Fe composite antibacterial agent prepared in Example 1.

[0026] Figure 4 Magnetic hysteresis (M-H) loop of the composite antibacterial agent prepared in Example 1.

[0027] Figure 5 Antibacterial effect diagram of the AC-NiO / Fe composite antibacterial agent in Example 2.

[0028] Figure 6 SEM images of the AC-NiO / Fe composite antibacterial agent contacting with bacteria in Example 2, wherein figure (a) is normal Escherichia coli; figure (b) is Escherichia coli treated by the AC-NiO / Fe antibacterial agent; figure (c) is normal Staphylococcus aureus; figure (d) is Staphylococcus aureus treated by the AC-NiO / Fe antibacterial agent.

[0029] Figure 7 Cyclic antibacterial experiment effect in Example 3, wherein figure (a) is the cyclic antibacterial experiment effect of the AC-NiO / Fe antibacterial agent on Escherichia coli; figure (b) is the cyclic antibacterial experiment effect of the AC-NiO / Fe antibacterial agent on Staphylococcus aureus.

[0030] Figure 8 Example 4 is the antibacterial effect of the AC-NiO / Fe composite antibacterial agent on Dianchi water, wherein figure (a) is without adding the AC-NiO / Fe antibacterial agent, and figure (b) is with adding the AC-NiO / Fe antibacterial agent.

[0031] Figure 9The spectrum scanning diagram of the AC-NiO / Fe composite antibacterial agent in Example 5 for adsorbing and degrading different dyes, wherein Fig. (a) is the adsorption and degradation effect on malachite green; Fig. (b) is the adsorption and degradation effect on methylene blue.

[0032] Figure 10 The influence of introducing different magnetic materials on the antibacterial performance in Comparative Example 1, wherein Fig. (a) is a blank control; Fig. (b) is the antibacterial effect of the antibacterial agent NiO / Fe2V4O 13 The antibacterial effect of the obtained antibacterial agent NiO / Fe2V4O 13 ; Fig. (c) is the antibacterial effect of the antibacterial agent NiO / CoFe2O4 obtained by combining NiO and CoFe2O4.

[0033] Figure 11 The antibacterial effect of the AC-NiO / Fe composite antibacterial agent synthesized by two methods in Comparative Example 2, wherein Figs. (a)-(c) are the antibacterial effect on E. coli; Figs. (d)-(f) are the antibacterial effect on Staphylococcus aureus; Figs. (a) and (d) are blank controls; Figs. (b) and (e) are the antibacterial effect of the AC-NiO / Fe composite antibacterial agent prepared by Method 1; Figs. (c) and (f) are the antibacterial effect of the AC-NiO / Fe composite antibacterial agent prepared by Method 2. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be further described below by means of specific embodiments in combination with the accompanying drawings, but the following examples are only simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0035] Unless otherwise specified, the reagents used in the present application are all commonly commercially available analytical pure.

[0036] Example 1

[0037] A preparation method of a recyclable antibacterial agent, specifically comprising the following steps:

[0038] (1) Taking Australian nut shells as raw materials, preparing activated carbon by a chemical activation method with phosphoric acid as an activator.

[0039] (2) Mixing NiCl2·6H2O and FeCl3·6H2O according to a molar concentration ratio of 1:2, then dissolving them in 20 mL of deionized water, and adjusting the pH to 11 with 1 mol / L NaOH to obtain a mixed solution.

[0040] (3) Transferring the mixed solution obtained in step (2) into a polytetrafluoroethylene-lined stainless steel autoclave, heating at 150°C for 2 h, then washing with distilled water and ethanol alternately for three times, and drying at 110°C overnight.

[0041] (4) The precipitate after drying in step (3) was calcined in a muffle furnace at 300°C for 4h to obtain a NiO / Fe composite material.

[0042] (5) 0.5g of the activated carbon obtained in step (1) and 0.5g of the NiO / Fe composite material obtained in step (4) were weighed, 20mL of distilled water was added, the impregnation and stirring time was 24h, the stirring speed was 200r / min, suction filtration was performed, and 60°C drying was performed overnight to obtain an AC-NiO / Fe composite antibacterial agent.

[0043] The antibacterial agent AC-NiO was also prepared by the following steps, and the specific preparation steps are as follows:

[0044] (1) The activated carbon was prepared by using the Australian nut shell as the raw material and phosphoric acid as the activating agent through a chemical activation method.

[0045] (2) 0.24g of NiCl2·6H2O was dissolved in 25mL of ethanol to form a green transparent solution, 1.46g of sodium acetate was dissolved in 10mL, 0.59g of sodium citrate was dissolved in 15mL of distilled water, the three solutions were mixed and stirred at 30°C for 30min to obtain a transparent solution, 0.5g of activated carbon powder was added, then the mixed solution was transferred to a hydrothermal reaction kettle, and kept at 140°C for 18h, and then naturally cooled to room temperature, the blue-green product was washed with deionized water and ethanol for five times respectively, and dried at 60°C for 4h, and finally annealed at 500°C for 2h in a furnace to obtain an AC-NiO material.

[0046] The SEM images of the AC-NiO / Fe composite antibacterial agent prepared in this example are shown in Figure 1 (a) and Figure 1 (b), from which it can be seen that the AC-NiO / Fe composite antibacterial agent mainly presents a segment rod-like structure loaded with nanoparticles. The oxides of Ni and Fe on the surface of the antibacterial agent are well dispersed; the EDS images of the AC-NiO / Fe composite antibacterial agent are shown in Figure 1 (c) ~ Figure 1 (f), from which it can be seen that Fe is successfully incorporated.

[0047] The AC-NiO / Fe composite antibacterial agent prepared in this example was subjected to X-ray photoelectron spectroscopy test, and the obtained XPS full spectrum is shown in Figure 2 , from which it can be seen that C, O, Ni and Fe exist in the AC-NiO / Fe composite antibacterial agent. In Figure 2 (a) and Figure 2As can be seen in (b), in the high-resolution spectrum of Ni 2p, there are two main peaks Ni 2p1 / 2 and Ni 2p3 / 2, respectively, at 873.3 eV and 855.7 eV, and there are obvious satellite peak characteristics at 861.7 and 879.1 eV, indicating that Ni in the AC-NiO / Fe composite antibacterial agent is mainly in the form of Ni 2+ O. Figure 2 As can be seen in (c), the high-resolution spectrum of Fe 2p, two strong peaks at 722.9 and 709.4 eV are observed, which are respectively attributed to Fe 2p1 / 2 and Fe 2p3 / 2. Among them, the peaks at 709.1 and 722.4 eV correspond to Fe 2+ O, the peaks at 711.6 eV and 725.1 eV correspond to Fe 3+ O, confirming the presence of Fe3O4, and the remaining 716.8 eV and 730.7 eV correspond to satellite peaks. Figure 2 In the high-resolution spectrum of O 1s in (d), the peak at 530.1 eV corresponds to M-O (M=Fe, Ni), and the peaks at 531.7 and 532 eV are related to adsorbed oxygen on the surface. According to the above analysis, it is further confirmed that the AC-NiO / Fe composite antibacterial agent is successfully prepared.

[0048] The oxygen vacancy concentrations of the AC-NiO / Fe composite antibacterial agent and the AC-NiO composite antibacterial agent prepared in this embodiment were tested by EPR, and the results are shown in Figure 3 As can be seen from the figure, AC-NiO and AC-NiO / Fe can produce EPR signals with a g value of 2.003. Compared with AC-NiO, AC-NiO / Fe shows a stronger EPR response, indicating that the incorporation of Fe can promote the generation of more oxygen vacancies. The extensive EPR signal comes from the magnetic interaction of Fe 3+ , Fe 2+ and , and the increase in oxygen vacancy concentration helps to improve the antibacterial performance of the material.

[0049] The activated carbon, AC-NiO antibacterial agent and AC-NiO / Fe antibacterial agent prepared in this embodiment were tested on a vibrating sample magnetometer (VSM) to record the material hysteresis loop. Under the applied external magnetic field intensity of 15000 Oe, the M-H loop was recorded; the M-H loop clearly shows the magnetic behavior of the composite antibacterial material, as shown in Figure 4 The activated carbon has almost no magnetism, and the AC-NiO and AC-NiO / Fe both have certain magnetism, and the remanence and coercivity of the two are relatively low, indicating that both materials exhibit superparamagnetic properties. As can be seen from the figure, the magnetism of AC-NiO is weak, and the magnetism of AC-NiO combined with Fe is significantly improved. After the material is used, it is sufficient to be magnetically separated by a magnetic field, facilitating the rapid recovery of the material after water disinfection treatment.

[0050] Example 2

[0051] Antibacterial performance test

[0052] The experimental bacteria used in this example are E. coli and S. aureus.

[0053] The antibacterial performance of the AC-NiO / Fe composite antibacterial agent obtained in Example 1, the AC-NiO antibacterial agent, the activated carbon and the NiO was tested by plate counting method, and the specific method is as follows:

[0054] In 10 mL of sterile water, add the antibacterial agent, and then add 100 μL of bacterial solution with a concentration of 10 3 CFU / mL to obtain a mixed solution, the final concentration of the antibacterial agent in the mixed solution is 300 μg / mL, and the final concentration of the bacterial solution is 10 5 CFU / mL. After the mixed solution is placed in a constant temperature shaker at 37°C for 15 min, 100 μL is coated on the LB culture medium, and then placed in a constant temperature incubator at 37°C for 16 h. The number of single bacteria is counted, and the mixed solution without adding the antibacterial agent is used as a control.

[0055] The results are shown in Figure 5 From the figure, it can be seen that before the incorporation of Fe, the antibacterial rate of AC-NiO against E. coli and S. aureus is 76.64% and 25.68% respectively, which is much higher than that of activated carbon, but the antibacterial performance against S. aureus is too poor to achieve the effect of broad-spectrum antibacterial. After the incorporation of Fe, the antibacterial rate against E. coli reaches 90.65%, and the antibacterial rate against S. aureus (S. aureus) reaches 96.85%, which is about 70% higher than that of AC-NiO. The incorporation of Fe has a more significant effect on S. aureus.

[0056] The physical damage of the material to the bacteria can be observed by SEM. The E. coli not treated by the AC-NiO / Fe composite antibacterial agent presents an intact rod-shaped structure, and the surface is smooth, as shown in Figure 6 (a), which shows that the bacteria are in a living state. The S. aureus not treated by any treatment presents a complete sphere, and there is no damage, as shown in Figure 6 (c). Figure 6(b) and (d) show the morphological changes of the two bacteria after AC-NiO / Fe composite antibacterial agent treatment. From the figure, it can be seen that the material is adsorbed to the surface of the bacteria, the bacteria are coated with the material, the antibacterial active ingredients react with the substances in the film, form depressions, and change the original morphology of the bacteria. This is mainly due to the ROS produced by the material, the entry of metal nickel ions and iron ions into the bacteria, causing internal oxidation of the bacteria, protein leakage and other conditions leading to bacterial death. And the material will produce electrostatic interaction after contacting with the bacteria, affecting the surface tension and membrane potential of the cell membrane, thereby destroying the cell integrity. In addition, the composite material has sharp micro-morphology that can pierce the bacteria, causing mechanical damage to the bacteria, leading to bacterial death

[0057] Example 3

[0058] Cycling performance test of AC-NiO / Fe composite antibacterial agent

[0059] The antibacterial durability and recyclability of the antibacterial material are crucial for the practical application of the antibacterial material.

[0060] In order to detect the recyclability and antibacterial durability of the material, 0.02 g of AC-NiO / Fe composite antibacterial agent was taken for antibacterial cycling experiment, 0.02 g of AC-NiO / Fe composite antibacterial agent was added into 10 mL of sterilized water, and then 100 μL of activated and diluted bacterial liquid containing 10 5 CFU / mL of E. coli and S. aureus was added, and after 15 min of shaking culture, the plate was coated, and after 16 h of culture, the viable bacteria count was performed, the antibacterial performance of the material in the first cycle was calculated, then the material and bacteria were separated by centrifugation at 8000 r / min for 10 min, and the material was washed with ethanol and distilled water and dried, and then the above experimental steps were repeated in turn for the next cycle experiment, and finally the antibacterial performance of the material in four cycle experiments was counted, and the reusability of the material was analyzed.

[0061] The experimental results are shown in Figure 7 As can be seen from Figure 7 (a), after four cycles, the antibacterial rate of AC-NiO / Fe composite antibacterial agent on E. coli was 66.58%, and as can be seen from Figure 7 (b), the antibacterial rate on S. aureus was 74.70%, indicating that the durability and stability of AC-NiO / Fe composite antibacterial agent were good.

[0062] Example 4

[0063] Study on the antibacterial effect of AC-NiO / Fe composite antibacterial agent on actual water body

[0064] The water body used in the experiment was taken from Dianchi Lake in Kunming City, Yunnan Province. 10 mL of Dianchi Lake water was added with the AC-NiO / Fe composite antibacterial agent, and the final concentration of the AC-NiO / Fe composite antibacterial agent in the Dianchi Lake water was 300 μg / mL. 100 μL of the Dianchi Lake water added with the AC-NiO / Fe composite antibacterial agent and the Dianchi Lake water without the AC-NiO / Fe composite antibacterial agent were coated in the LB culture medium after the Dianchi Lake water added with the AC-NiO / Fe composite antibacterial agent was placed in a constant-temperature shaker at 37℃ for 15 min, and cultured for 16 h.

[0065] As shown in Figure 8 , it can be seen from Figure 8 (a) that the water without AC-NiO / Fe composite antibacterial agent treatment grew a lot of bacteria, Figure 8 It can be seen from (b) that the experimental group treated with the AC-NiO / Fe composite antibacterial agent can remove more than 99% of various bacteria in the Dianchi Lake water, indicating that the composite antibacterial material prepared in the application has a good inhibitory effect on the growth and reproduction of bacteria in the Dianchi Lake water.

[0066] Example 5

[0067] The adsorption effect test of organic dyes malachite green and methylene blue was carried out, and the specific steps are as follows:

[0068] Malachite green and methylene blue solutions with a concentration of 10 μg / L were prepared respectively, 2 μg of the AC-NiO / Fe composite antibacterial agent was added into 50 mL of the malachite green and methylene blue solutions respectively, and the organic dyes in the solutions were detected at 5, 15, 30, 60, 90 and 120 min, and the results are shown in Figure 9 , from Figure 9 (a) is the adsorption and degradation spectrum scanning diagram of malachite green, Figure 9 (b) is the adsorption and degradation spectrum scanning diagram of methylene blue dye, and from the figure it can be seen that the characteristic peak decreases more after 120 min, indicating that the AC-NiO / Fe composite antibacterial agent has the function of adsorbing and degrading organic dyes.

[0069] Comparative Example 1

[0070] In this embodiment, different antibacterial agents were prepared by combining NiO with Fe2O3, Fe2V4O 13 and CoFe2O4, and the preparation method is as follows:

[0071] (1) The preparation method of the NiO / Fe2O3 is as follows: 0.1 g of nickel oxalate is added into 10 mL of water, and after ultrasonic dissolution, 0.0066 g of iron nitrate nonahydrate is added, and then transferred into 50 mL of sodium hydroxide solution with a concentration of 3 mol / L, stirred at 40 ℃ for 10 min, centrifuged at 8000 r / min, washed with water and ethanol alternately, dried at 60 ℃ for 2 h, and calcined at 450 ℃ for 0.5 h to obtain the NiO / Fe2O3 composite antibacterial material.

[0072] (2) The preparation method of the NiO / Fe2V4O 13 is as follows: 0.702 g of NH4VO3 is added into 200 mL of water, and then 0.808 g of iron nitrate nonahydrate and 0.5 g of NiO are added and stirred for 4 h, and then filtered, and dried at 60 ℃ for 10 h to obtain the NiO / Fe2V4O 13 composite antibacterial material.

[0073] (3) The preparation method of the NiO / CoFe2O4 is as follows: 10 mmol of iron nitrate nonahydrate and 5 mmol of cobalt chloride hexahydrate are dissolved in 100 mL of water, 15 mmol of citric acid is dissolved in 100 mL of water, the above two solutions are mixed, and then 0.5 g of NiO is added, stirred at 60 ℃ for 1 h, dried at 90 ℃ for 24 h, and calcined at 300 ℃ for 2 h to obtain the NiO / CoFe2O4 composite antibacterial material.

[0074] The above-prepared materials are subjected to antibacterial performance test, the bacteria used in the experiment are Escherichia coli, the experimental method refers to Example 2, and the experimental results are shown in Figure 10 , Figure 10 (a) is a blank control, and the number of single bacterial colonies is 539, Figure 1 (b) is the antibacterial effect of the antibacterial agent NiO / Fe2V4O 13 obtained by combining NiO and Fe2V4O 13 , and the number of single bacterial colonies is 275, Figure 1 (c) is the antibacterial effect of the antibacterial agent NiO / CoFe2O4 obtained by combining NiO and CoFe2O4, and the number of single bacterial colonies is 229, Figure 1 (d) is the antibacterial effect of the antibacterial agent NiO / Fe2O3 obtained by combining NiO and Fe2O3, and the number of single bacterial colonies is 164, from the number of single bacterial colonies in the figure, it can be seen that the antibacterial rate of NiO combined with Fe2O3, Fe2V4O 13 and CoFe2O4 can reach 69.6%, and the antibacterial effect is poorer than that of the AC-NiO / Fe composite antibacterial agent prepared in the application.

[0075] Comparative Example 2

[0076] In the example, the AC-NiO / Fe composite antibacterial agent is obtained by two different preparation methods

[0077] Method one: 1.9 g of iron chloride hexahydrate and 5.6 g of sodium acetate were dissolved in 70 mL of ethylene glycol, and hydrothermal treatment was carried out at 200°C for 12 h. Centrifugation was carried out at 5000 r for 10 min, and ethanol washing was carried out three times. Drying was carried out at 70°C for 12 h to obtain Fe3O4. Further, 0.2 g of Fe3O4 and 0.5 g of activated carbon (prepared by chemical activation method using Australian nut shells as raw materials and phosphoric acid as an activating agent) were added in the process of synthesizing NiO to obtain the AC-NiO / Fe composite antibacterial agent.

[0078] Method two: 0.5 g of activated carbon (prepared by chemical activation method using Australian nut shells as raw materials and phosphoric acid as an activating agent), 0.72 g of nickel chloride hexahydrate and 1.9 g of iron chloride hexahydrate were added to 60 mL of water, and the pH was adjusted to 11 by NaOH. Hydrothermal treatment was carried out at 150°C for 2 h. Drying was carried out at 110°C overnight, and calcination was carried out at 300°C for 4 h to obtain the AC-NiO / Fe composite antibacterial agent.

[0079] The two antibacterial agents prepared in this example were subjected to antibacterial performance tests. The experimental method was as described in Example 3, and the experimental results are shown in Figure 11 Figure 11 (a) Figure 11 (c) is the antibacterial effect on Escherichia coli, Figure 11 (d) Figure 11 (f) is the antibacterial effect on Staphylococcus aureus; Figure 11 (a) and Figure 11 (d) are blank controls, Figure 11 (b) and Figure 11 (e) are the antibacterial effects of the AC-NiO / Fe composite antibacterial agent prepared by method one, Figure 11 (c) and Figure 11 (f) are the antibacterial effects of the AC-NiO / Fe composite antibacterial agent prepared by method two. According to statistical calculation, the antibacterial rate of the AC-NiO / Fe composite antibacterial agent prepared by method one on Escherichia coli is 39.5%, and the antibacterial rate on Staphylococcus aureus is 79%. The antibacterial rate of the AC-NiO / Fe composite antibacterial agent prepared by method two on Escherichia coli is 73.3%, and the antibacterial rate on Staphylococcus aureus is 51.3%. The antibacterial effects of the AC-NiO / Fe composite antibacterial agents prepared by the two methods are not as good as the antibacterial effect of the AC-NiO / Fe composite antibacterial agent prepared by the method described in the present application.​

Claims

1. A method for preparing a recyclable composite antimicrobial agent for water treatment, characterized by: Specifically comprising the following steps: (1) using macadamia nut shell as raw material, preparing activated carbon by chemical activation method with phosphoric acid as activator; (2) dissolving NiCl2·6H2O and FeCl3·6H2O after mixing, adjusting pH value to 11; (3) transferring the mixed solution obtained in step (2) into a polytetrafluoroethylene-lined stainless steel autoclave, carrying out hydrothermal reaction, filtering, washing and drying the obtained precipitate overnight; (4) calcining the dried precipitate in step (3) in a muffle furnace to obtain NiO / Fe composite material; (5) stirring and impregnating the activated carbon obtained in step (1) and the NiO / Fe composite material obtained in step (4) in water, suction filtering and drying to obtain AC-NiO / Fe composite antibacterial agent.

2. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The molar concentration ratio of NiCl2·6H2O and FeCl3·6H2O in step (2) is 1:

2.

3. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The pH value in step (2) is adjusted to 11 using 1 mol / L NaOH.

4. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The hydrothermal reaction conditions in step (3) are heating at 150℃ for 2h, the washing method is alternating washing with distilled water and ethanol for three times, and the drying conditions are 110℃.

5. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The calcination conditions in step (4) are calcination at 300℃ for 4h.

6. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The addition amount of NiO / Fe composite material in water in step (5) is 0.025g / mL, and the addition amount of activated carbon is 0.025g / mL.

7. The method for preparing the recyclable composite antibacterial agent for water treatment according to claim 1, characterized by: The stirring and impregnation time in step (5) is 24h, and the stirring speed is 200r / min.

Images